Spark-plug.



R. JAKE.

SPARK PLUG. APP LIOATION FIL ED JUNE 9, 1909. RENEWED APR. 21, 1910.961,136. Patented June 14,1910.

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SIARK-PLUG.

Specification of Letters Patent,

Patented June 14,1910.

Application filed ham a, 1900, Serial No. 501,039. v Renewed April 21,1910. Serial no. 556,848.

herebvdeclare the following to be a full,

clear, and exact description of the invention, such as will enableothers skilled in the art to which it appertains to make and use thesame. r

This invention relates to spark plugs such as are used in connectionwith internal combustion engines. 'It is a well known fact] that thesparking terminals of plugs of this character are extremely apt tobecome unfastened after a short period of use by reason of thedeposition on the sparkin surface of an accumulation of soot and Oll. Itis also well understood that sparking tenninals in plugs of thischaracter are apt to f pit under the influence of the electric dischargewith the consequence that the sur face is roughened and the depositsthat accumulate are rendered difli'cult to remove.

The principal object of the present invention is to provide an improvedform of spark plug which shall have a form ofspar'king terminal notadapted to receive and retam theseaccumulations and which will not i 3pit -1 7 With the above and other objects in view the invention consistsof a spark plug having an improved form of body together with improvedterminals carriedthereby.

The inventionfurtherconsists in certain novel details 'of constructionand combina; tions of parts hereinafter fully described,

and specifically set forth in the. claims.

In the'accompanyi drawings, like characters of reference indicate likeparts in the several views, and :,Figure 1 is a vertical section of aspark cordance with this I enlarged detail view of the sparkingtermiplug constructed in acnals.

The plug body comprises a threaded pertion 10 adapted to be screwed intothe wall of an explosiveengine cylinder and this threaded portion isprovided with the usual nut 11 so that it may be screwed firmly in bymeans of a suitable wrench: Extending from the threaded portion 10 is abody 12 and upon the lowerend of this body is a invention. Fig. 2 is'an'minal 18 and the insulation thereof is indicated at 19 and is providedwith a collar '20 1 which prevents the terminal being inserted too farin the body by reason of this collar bearing against the shoulderforined between the opening 16 and enlarged portion 17 Screwed over theenlarged portion 17' is a packing gland 21 andbetween the upper end ofthis packing gland and the collar 20 is suitable elastic packing 22. Theinsulation cap 23 the cap being means of suitable threads formed on saidterminal and in an opening in the cap. A binding screw 24 is held on theterminal beyond the cap so that a wire may be retained between the capand binding screw. The lower end of this terminal is squared so that theend is formed by a plane perpendicplar to. the axis of the terminal.Within-the threaded opening 15 is screwed aterminal 25 provided with acup shaped'depression 26 in the face proximal theterminali-l8 and thisterminal 25 is further provided with a suitable screw driver receivingslotor the like as indicated at 27 this being for the purpose ofadjusting the distance between the opposed terminals. The relative sizesof the terminals 18 and 25 is such thatithe cup shaped depression in thelatter will be as large, or

slightly larger than the end vof the ter- .minal 18.

In the operation of this plug when a spark passes from one terminal'tothe other it jumps from. the edge of the squared ofi terminal .to therimof the cup and as this rim or edge becomes slightly worn the lengthof the gap will be increasedand the spark will move around to a freshposition thus traveling continuously around the terminals and nevercontinuing long enough in one position to pit the terminals Further- '19is reduced at the upper end and on this more, it is experimentally foundthat with.

this construction the deposition of soot on the terminals is practicallyobviated and that an extremely fat and eflicient spark .is obtained. I

There has thus been rovided a simple and eflicient device of the inddescribed and for the purpose specified.

Having thus described the invention, what is claimed as new, is

1. In a spark plug, a'bodyprovided with an opening therethrough, anintegral yoke on said body provided with a threaded sparking terminalopening, a sparking ter minal fixedly held in .the body, and a threadedsparking terminal held in the threaded opening and tprovided with mdansto engage a tool, one 0 said terminals being provided with a cup shapedend. 7

2. In a spark plug,-a body provided with an opening therethrough, anintegral yoke on said body provided with a threaded sparking terminalopening, a sparking terminal fixedly held in the body, and a threadedsparking terminal held'in the threaded opening an provided with means toengage a tool, one of said terminals being provided sparking terminalopening,

with a cup shaped end and the other ter-- minal having an end cut atright angles to the body.

3. In a spark plug, a body provided with an opening therethrough, anintegral yoke on said body provided with a threaded a sparking terminalfixedly held in the body, and a threaded sparking terminal held 111 thethreaded opening and provided with means to engage a tool, one of saidterminals being provided with a cup shaped end and the other terminalhaving an end cut at right angles to the body,- the cup shaped end beingof grgater diameter than the o posed terminal en In testimony whereof, Iafii'x my signature, in presence of two witnesses;

ROBERT JAKE. Witnesses:

CHARLES PETERS, J. S. COWLEY.

